The present invention relates in general to semiconductor devices, and more particularly to circuit boards for supporting semiconductor devices.
Electronic systems often use printed circuit boards to mount semiconductor devices for structural support, interconnection, and connecting to other system components. For high frequency systems, the semiconductor devices typically are soldered directly to wiring traces on the board to minimize signal degradation from inductive and capacitive parasitics caused by excess lead lengths. The circuit boards are fabricated from a substrate material which is mechanically rugged and has the desired dielectric properties. A typical circuit board comprises multiple layers, each of which has a surface which can include wiring traces for interconnecting system components. Traces on one layer can be connected to a trace on a different layer by means of a via to allow conduction perpendicular to the surfaces having wiring traces. The thickness of a layer can be selected so that the wiring traces operate as a waveguide or transmission line to propagate high frequency signals.
Many prior art systems insert a semiconductor device in a socket to perform qualification, reliability, or other long term testing, which allows defective devices to be easily identified and replaced. However, the use of sockets makes it more difficult to identify defective devices in the first place because the socket leads have the effect of extending the lead length of the semiconductor device, which degrades signals and results in the test environment being unrepresentative of the actual system operation.
Other prior art systems avoid excess lead lengths by soldering the devices directly to the board for testing. However, when a defective device is found, the device must be desoldered from the board and replaced, a time consuming and expensive process which can damage the printed circuit board or other system components.
Hence, there is a need for a circuit board and method of testing which provides a reliable yet temporary connection to system components without requiring excess lead lengths or the need to solder the semiconductor device to the circuit board.